SECTION 27 Equipment and Accessories EMS-002 Cryo Workstation (continued)
Accessories 1. Freeze Substitution Module for EMS-002 Cryo Workstation Part # 34765
In the 1980s descriptive ultrastructure analysis essentially came to the end and microscopists found they needed to correlate structure with function to advance their research. About the same time biochemists and molecular biologists were able to see where molecules interacted with cellular membranes. It was essential to marry the work of the structural biologists to the functional biologists by preserving the ultrastructure in the antigenicity of the tissue. During this research it was determined early on that conventional methods of fixation using chemicals were unsuitable for such studies because of the extensive redistribution of proteins, extraction of cytoplasmic constituents, and destruction of cellular antigenicity.
Freeze substitution, which is the dissolution of freezing water (ice) in the frozen specimen at low temperature has turned out to be one of the most powerful techniques in electron microscopy. The dissolution of the ice within the specimen is achieved by substituting water molecules with molecules of an inorganic solvent like acetone, while simultaneously fixing the biological material with Osmium tetroxide and blocks staining with Uranyl acetate. This slow dissolution of the ice takes place over many hours at slowly increasing temperatures. Once the substitution process is complete the samples can be infiltrated and embedded with a wide range of Epoxies or Acrylics. It is even possible to perform a low temperature embedding at -50˚ Celsius using specialized resins. The end results are beautifully preserved specimens possessing both antigenicity for your immuno-localization studies and perfect structural relationship for descriptive ultrastructure analysis.
The EMS-002 Freeze substitution module is a simple cost-effective method to achieve freeze substitution. Once your samples are frozen on the EMS-002 Cryo Workstation the cryogen condensation module can be removed from the stainless steel Dewar and replaced with the substitution chamber. The freeze substitution controller will control the liquid nitrogen levels automatically as well as the substitution process itself. The user just has to monitor the systems progress during substitution and perform scheduled substitution media changes.
Freeze Substitution Controller
1. Programmable Substitution Temperature Controller: Comes preprogrammed from the factory to control precise ramp/soak times and temperatures critical to successful freeze substitution
2. Liquid Nitrogen Level Controller:
Since the substitution process runs over the course of many days using published protocols, the LN2 controller insures that LN2 levels inside the Dewar are maintained at a level appropriate for the process step being executed.
Freeze Substitution Chamber 1 7 2 3 5 4 6 2. Cryo-TEM Transfer Interface Part # 37000-T
It is possible to directly transfer your vitrified samples using the Cryo-TEM transfer interface, along with your Gatan 3500 series ultra-low temperature, till rotate specimen holders. The transfer interface allows the direct insertion of Gatan cryo-holder into the plunge freezers liquid nitrogen dewar. This will allow easy cryogenic transfer of the vitrified sample directly to the microscope via the 3500 cryo-holder right from the work platform within the dewar. Please consult the EMS product manager for options as the transfer holder is not compatible with all possible plunge freezer configurations.
1. Transfer tool enables users move the substitution chamber in and out of the substitution chamber while at cryogenic temperatures.
2. Vacuum insulated stainless steel LN2 Dewar (Part of the Plunge Freezer)
3. Substitution chamber acts as the main heat sink and control interface for the substitution chamber.
4. Substitution holders large mass enhances temperature stability for the samples and media.
5. Substitution Media Vials Holders: Allows users to store extra substitution media at the correct process temperature for solution exchanges as required by the protocol being used.
6. Specimen Vials Holders: Containers for the tissue being substituted as well as the substitution media.
7. Substitution Chamber Lid: Helps maintain Dewar temperature stability and a pure Nitrogen gas atmosphere. Also excludes water vapor from the substitution chamber.